The Ventura-based emissions control manufacturer reported a net loss of $2.8 million for the quarter, or 39 cents per diluted share, compared with net income of $500,000, or 6 cents per share, a year earlier. Revenue for the quarter was $12.4 million, down 41.8 percent from a year earlier.

For fiscal year 2012, revenue was down 1.7 percent from the previous year, to $60.5 million, and Clean Diesel suffered a net loss of $1.34 per diluted share.

In a statement, CEO Craig Breese said the company did not achieve its financial objectives in 2012 and the fourth quarter was challenging.

“We expected greater retrofit sales under the California truck and bus mandate and believe that the late and weak regulation enforcement coupled with a delayed product approval were contributing factors,” he said.

The company’s stock price ended Friday down 24 cents, at $2.22 a share.